The emergence of portable electronic computing platforms allows functions and services to be enjoyed wherever necessary. Palmtop computers, personal digital assistants, mobile phones, portable game consoles, biometric/health monitors, remote controls, digital cameras, to name a few, are some daily-life examples of portable electronic computing platforms. The desire for portability has driven these computing platforms to become smaller and, consequently, to have longer battery life. A dilemma occurs when these ever-smaller devices require efficient ways to collect user input.
Portable electronic computing platforms need these user inputs for multiple purposes, including (a) navigating a cursor or a pointer to a certain location on a display, (b) selecting (e.g., choosing or not choosing) an item or an action, and (c) orientating (e.g., changing direction with or without visual feedback) an input device.
Concepts for user input from much larger personal computers have been borrowed. Micro joysticks, navigation bars, scroll wheels, touch pads, steering wheels and buttons have all been adopted, with limited success, in conventional devices. All these positioning devices consume substantial amounts of valuable surface real estate on a portable device. Mechanical positioning devices such as joysticks, navigation bars and scroll wheels can wear out and become unreliable. Their sizes and required movements often preclude optimal ergonomic placement on portable computing platforms.
Prior art methods calculate rotation by rotating one frame with respect to another and then applying standard correlation methods. These methods require the selection of a pivot point (e.g., the origin), followed by additional computations. These computations are not helpful for determining linear motion (e.g., non-rotational movement in the x- and y-directions). Such a shortcoming makes prior art systems even more inefficient when used in portable devices, in which both rotational and linear movement are required, such as when emulating, respectively, a steering wheel and a pointing device.